A review of the work by Stellenbosch University to assess lignocellulosic biorefineries by means of simulation and experimental work with a focus on the simulation of sugarcane biorefineries.
Kate Haigh and Johann Gorgens
One approach to address increasing concerns about the impact on our planet is to investigate alternative feedstocks for the production of biofuels and biochemicals. In this regard processing of non-food fibrous biomass has received great attention because of the wide range of potential biochemicals which can be produced. Typical examples of such lignocullolosic biomass include straw, sugarcane bagasse, triticale and harvest residues,. Steam explosion pre-treatment can be used to produce a digestible cellulose fraction from the biomass and a recent study has investigated the optimum conditions to produce ethanol from triticale (a straw crop grown in the Western Cape). This type of process typically degrades the lignin and hemicellulose fractions so an alternative approach is to investigate fractionation using solvents such as ionic liquids and organasolv with the target at producing minimally degraded lignin, oligomeric hemicellulose and digestible cellulose. In addition to bioethanol it is possible to produce a wide range of other chemicals from biomass including butanol, furfural and lactic acid leading to the development of a variety of potential biorefinery scenarios.
There are various trade-offs to consider in terms of processing conditions, the number of process steps and final product quality. In order to investigate this further, Aspen simulations integrated with economic, environmental and social impact assessments can be used to compare options. This approach also permits the comparison of substantially different processes resulting in different products from the same biomass. The potential to annex a biorefinery to a sugar mill by making more effective use of the sugarcane bagasse and harvest residues is currently being investigated. This study includes laboratory experiments to investigate processing options for the production of lactic and furfural as well as simulation modelling to generate potential biorefinery scenarios based on literature data.
This seminar will provide an overview of the lignocelluosic processing options currently being investigated at Stellenbosch University followed by a more detailed discussion on sugarcane biorefinery simulation research.